Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 653789FA324 for ; Mon, 4 Dec 2006 12:41:22 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-new, port 10024) with ESMTP id 93600-08 for ; Mon, 4 Dec 2006 12:41:17 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from gollum.cambrium.nl (gollum.cambrium.nl [217.19.16.130]) by postgresql.org (Postfix) with SMTP id 043B69FA2CC for ; Mon, 4 Dec 2006 12:41:16 -0400 (AST) Received: (qmail 29132 invoked from network); 4 Dec 2006 16:41:15 -0000 Received: from office.tweakers.net (HELO ?10.0.0.169?) (84.245.2.46) by gollum.cambrium.nl with SMTP; 4 Dec 2006 16:41:15 -0000 Message-ID: <45744FAA.20603@tweakers.net> Date: Mon, 04 Dec 2006 17:41:14 +0100 From: Arjen van der Meijden User-Agent: Thunderbird 1.5.0.8 (Windows/20061025) MIME-Version: 1.0 To: Tom Lane CC: pgsql-performance@postgresql.org Subject: Re: 8.2rc1 (much) slower than 8.2dev? References: <4573D1F7.600@tweakers.net> <16696.1165244024@sss.pgh.pa.us> In-Reply-To: <16696.1165244024@sss.pgh.pa.us> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200612/47 X-Sequence-Number: 22103 Tom Lane wrote: > Arjen van der Meijden writes: >> I'll run another analyze on the database to see if that makes any >> difference, but after that I'm not sure what to check first to figure >> out where things go wrong? > > Look for changes in plans? Yeah, there are a few number of small changes in plans and costs estimated. I've a large list of queries executed against both databases, and I haven't seen any differences in row-estimates, so the analyze's have yielded similar enough results. I'm not sure whether some of the changes are for better or worse, you can probably spot that a bit faster than I can. I saw a few index scans replaced by seq scans (on small tables), all index scans seem to have doubled in cost? And I saw a few bitmap scans in stead of normal index scans and more such small changes. But not so small if you execute a hundreds of thousands of those queries. Since I'd rather not send the entire list of queries to the entire world, is it OK to send both explain analyze-files to you off list? Best regards, Arjen